The data communication equipment is composed of a plurality of line cards and fabric switch boards, wherein the line cards and the fabric switch boards are connected to each other crosswise and vertically. After receiving from an upstream device the packets with various lengths going to different destinations, the line card at the input end transmits the packets to a Packet Processor (PP), which searches for a routing table according to the packet destinations so as to determine an output end, and transmits the packets to a Traffic Management (TM). After being shaped by the TM, the packets are split into a plurality of cells with a fixed size at a Fabric Switch Interface (FI). The cells are continuously sent to the fabric switch. The fabric switch selects a path for each cell independently and transmits the cells to a destination port.
Since different cells may be transmitted through different paths of the fabric switch, the cells arriving at the destination port may be disordered (i.e., the cells belonging to a same packet do not arrive sequentially in their positional orders in the packet), thus the disordered cells need to be reordered (resequence) and the cells belonging to the same packet shall be reassembled into a complete packet. Next, the packets sent by a same source port are arranged in their sending sequences at the source port, and finally sent to a downstream device from the output port. In which, the series of operations, i.e., reassembling the cells of the same packet into a complete packet, arranging the packets sent by the same source port in their sending sequences at the source port, etc. are generally called as packet reassembly and reordering. In the prior art, the packets of various sources are usually reassembled and reordered at the destination port using the time scales. This method has a high requirement for the time scale synchronization. But when there are many sources, it is difficult to achieve very accurate time scale synchronization, thus this method is not suitable for equipment with high performance. However, if the packets are simply reordered based on the sources at the destination port without using the time scales, a lot of memories and control resources will be wasted.